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  1. antigen
    any molecule that is recognized as foreign by an organism and that therefore stimulates the production of specific protein molecules called antibodies.
  2. antibody
    a protein molecule that recognizes and binds to the foreign substance introduced into the organism as part of the immune response to remove the foreign antigen from the body.
  3. complete recessiveness
    the recessive allele is phenotypically expressed only when it is homozygous
  4. incomplete dominance
    (also referred to as semidominance or partial dominance) the phenotype of the heterozygote lies in the range between the phenotypes of individuals that are homozygous for either allele involved.
  5. codominance
    the heterozygote exhibits the phenotypes of both homozygotes.
  6. haplosufficient
    the condition where one copy of a gene in a diploid organism is sufficient to give a normal phenotype.
  7. lethal allele
    an allele that results in the death of an organism
  8. essential genes
    genes that, when mutated, can result in a lethal phenotype
  9. dominant lethal allele
    both homozygotes and heterozygotes for that allele show the lethal phenotype
  10. recessive lethal allele
    homozygotes for that allele have the lethal phenotype
  11. expressivity
    the degree to which a penetrant gene or genotype is phenotypically expressed in an individual
  12. sex-limited traits
    genes that are autosomes affect a particular phenotype that appears in one sex, but not the other
  13. sex-influenced traits
    traits often are controlled by autosomal genes. such traits appear in both sexes, but either the frequency of occurrence in the two sexes is different or the relationship between genotype and phenotype is different.
  14. norm of reaction
    the range of potential phenotypes that a single genotype could develop if exposed to a range of environmental conditions
  15. maternal effect
    the phenomenon in which a phenotype of the offspring is determined not by the genotype of the offspring but by the nuclear genotype of the mother, with no influence by the paternal nuclear genome.
  16. complementation test (the cis-trans test)
    which determines whether two independently isolated mutants with the same phenotype have mutations in the same or different genes.
  17. epistasis
    the interaction between alleles of two or more genes to control a single phenotype
  18. recessive epistasis
    A/- b/b and a/a b/b individuals have the same phenotype, which results in a phenotypic ratio in the F2 of 9:3:4
  19. dominant epistasis
    A/- B/- and A/- b/b individuals have the same phenotype, so the phenotypic ratio in the F2 is 12:3:1
  20. duplicate recessive epistasis
    a/a is epistatic to B and b, and b/b is epistatic to A and a.
  21. duplicate dominant epistasis
    A is epistatic to B and b, and B is epistatic to A and a.
  22. suppressor gene
    when a modifier gene shifts the phenotype associated with a mutant allele of another gene toward the phenotype associated with the wild-type allele of that gene
  23. extranuclear inheritance (non-Mendelian inheritance)
    the pattern of inheritance shown by extranuclear genes
  24. the four main characteristics of extranuclear inheritance
    • 1. ratios typical of Mendelian segregation are not found, because meiosis-based Mendelian segregation is not involved.
    • 2. in multicellular eukaryotes, the results of reciprocal crosses involving extranuclear genes are not the same as reciprocal crosses involving nuclear genes, because meiosis-based Mendelian segregation is not involved.
    • 3. extranuclear genes cannot be mapped to the chromosomes in the nucleus
    • 4. extranuclear inheritance is not affected by substituting a nucleus with a different genotype.
  25. uniparental inheritance
    all progeny have the phenotype of only one parent.
  26. maternal inheritance
    the phenotype of the mother is inherited exclusively
  27. heteroplasmons (cytohets)
    individuals that have a mixture of mutant and normal mitochondria
  28. genetic marker
    another name for a mutation or variant that gives a distinguishable phenotype
  29. recombinants
    nonparental combinations of linked alleles
  30. physical markers
    cytologically detectable visible changes in the chromosomes that make it possible to distinguish the chromosomes and, hence, the results of crossing-over under the microscope.
  31. coupling (cis configuration)
    the pairing of alleles to match each other (w+ m+ and w m)
  32. repulsion (trans configuration)
    each homolog carries the wild-type allele of one gene and the mutant allele of the other gene (w+ m and w m+)
  33. interference
    the presence of one crossover interferes with the formation of another crossover nearby
  34. coefficient of coincidence
    • the expressed extent of interference
    • observed double crossover frequency/expected double crossover frequency
  35. mapping functions
    mathematical formulas that define the relationship between map distance and recombination frequency.
  36. the lod score method
    used to analyze pedigrees for possible linkage between two loci
  37. minimal medium
    simplest set of chemicals needed for the organism to grow and survive
  38. complete medium
    supplies vitamins and amino acids and all kinds of substances that might be expected to be essential metabolites and whose biosynthesis might be interfered with by mutation.
  39. auxotrophs
    strains of bacteria that are unable to synthesize essential nutrients
  40. prototroph
    a bacterial strain that is wild type and thus can synthesize all essential nutrients
  41. conjugation
    a process in which there is a unidirectional transfer of genetic information through direct cellular contact between a donor bacterial cell and a recipient bacterial cell.
  42. transconjugants
    recipients that have incorporated a piece of donor DNA into their chromosomes
  43. transformation
    the unidirectional transfer of extracellular DNA into cells, resulting in a phenotypic chance in the recipient.
  44. heteroduplex DNA
    a region of DNA with different sequence information on two strands
  45. transduction
    a process by which bacteriophages transfer genes from one bacterium to another
  46. fine-structure mapping
    the detailed genetic mapping of sites within a gene
  47. cis-trans test (complementation test)
    to find out whether two different mutants belonged to the same gene.
  48. chromosomal mutations
    variations from the normal (wild type) condition in chromosome structure or chromosome number
  49. pseudodominance
    expression of a recessive trait, caused by the absence of a dominant allele
  50. duplication
    a chromosomal mutation that results in the doubling of a segment of a chromosome
  51. inversion
    a chromosomal mutation that retults when a segment of a chromosome is excised and then reintegrated at an orientation 180 degrees fromt the original orientation
  52. paracentric inversion
    does not include the centromere
  53. pericentric inversion
    includes the centromere
  54. dicentric bridge
    when one recombinant chromatid becomes stretched across the cell as the two centromeres begin to migrate in anaphase
  55. dicentric chromosome
    a chromosome with two centromeres
  56. translocation
    a chromosomal mutation in which there is a change in position of chromosome segments and the gene sequences they contain to different location in the genome
  57. proto-oncogene
    a gene that, in normal cells, controls the normal proliferation of cells
  58. oncogene
    a gene that encodes a protein which plays a role in the transition from a differentiated cell to a tumor cell with an uncontrolled pattern of growth.
  59. position effect
    a change in the phenotypic expression of one or more genes as a result of a change in position in the genome
  60. epigenetics
    a meiotically or mitotically heritable change in gene expression that does not involve a change in the DNA sequence of the affected genes.
  61. euploid
    when an organism or a cell has one complete set of chromosomes or an exact multiple of complete sets
  62. aneuploidy
    chromosome mutations resulting in variations in the number of chromosome sets occur in nature
  63. nullisomy
    involves a loss of one homologous chromosome pair (2N-2)
  64. monosomy
    involves a loss of a single chromosome (2N-1)
  65. trisomy
    involves a single extra chromosome, the cell has three copies of a particular chromosome and two copies of all other chromosomes. (2N+1)
  66. tetrasomy
    involves an extra chromosome pair, there are four copies of one particular chromosome and two copies of all other chromosomes (2N+2)
  67. trisomy-21
    occurs when there are three copies of chromosome 21.
  68. robertsonian translocation
    a different sort of chromosomal mutation called centric fusion which produces three copies of the long arm of chromosome 21.
  69. trisomy-13
    produces Patau syndrome
  70. trisomy-18
    produces Edwards syndrome
  71. regulated genes
    genes whose activity is controlled in response to the needs of a cell or organism
  72. constitutive genes
    genes are always active in growing cells
  73. inducer
    the regulatory substance that brings about gene induction
  74. induction
    the phenomenon of producing a gene product in response to an inducer
  75. effectors
    a class of small molecules that help control the expression of many regulated genes
  76. beta galactosidase
    an enzyme that breaks down lactose into galactose and glucose, as well as catalyzing the isomerization of lactose to allolactose, a compound that is important in regulating expression of the lac operon.
  77. lactose permease
    a protein, found in the e. coli cytoplasmic membrane, actively transports lactose in the cell.
  78. beta galactoside transacetylase
    an enzyme that transfers an acetyl group from acetyl-CoA to beta glactosides.
  79. polycistronic mRNA
    one single mRNA molecule with three clustered genes
  80. cis-dominant
    a gene or DNA sequence that controls only genes located on the same contiguous piece of DNA.
  81. trans-dominant
    when two genes are located on different DNA molecules
  82. operon
    a cluster of genes, the expressions of which are regulated together by operator repressor protein interaction, plus the operator region itself and the promoter.
  83. catabolite activator protein
    a dimer of two identical polypeptides that binds to the CAP site along with cAMP (this makes the CAP-cAMP complex that is the positive-regulator molecule), which is upstream of the site where RNA polymerase binds to the promoter, CAP then recruits RNA polymerase to the promoter and transcription is initiated.
  84. aporepressor protein
    the product of trpR, which is basically an inactive repressor that alone cannot bind to the operator.
  85. attenuation
    what terminates short transcripts
  86. general transcription factors
    these bind to the promoter and recruit RNA polymerase II. only a low, basal level of transcription occurs with only general transcription factors.
  87. activators
    stimilate transcription initiation
  88. coactivators
    a large multiprotein complex that does not bind directly to DNA, but participates in the activation of transcription by interacting both with activators and with GTFs.
  89. repressors
    inhibit the activation of transcription initiation by activators
  90. corepressors
    analogous to the recruitment of coactivators by activators
  91. steroid hormone response elements
    where the steroid receptor complex binds during gene regulation
  92. hypersensitive sites (hypersensitive regions)
    regions of DA around transcriptionally active genes that are more highly sensitive to digestion by DNase I.
  93. chromatin remodeling
    the process of a chromatin structure being altered in the vicinity of the core promoter
  94. nucleosome remodeling complexes
    large multiprotein complexes that remodel chromatin by using the energy of ATP hydrolysis
  95. gene silencing
    a phenomenon whereby a gene is transcriptionally silent due to its location
  96. genomic imprinting
    an epigenetic phenomenon in which the expression of certain genes is determined by whether the gene is inherited from the female or male parent.
  97. alternative polyadenylation
    used to produce different pre-mRNA molecules
  98. alternative splicing
    used to produce different functional mRNA's
  99. RNA interference (RNAi or RNA silencing)
    when small regulatory RNA molecules silence gene expression in eukaryotes
  100. microRNA's (miRNA's)
    noncoding, single stranded regulatory RNA molecule about 21-23 nucleotides long derived from an RNA transcript. It regulates the expression of a target mRNA by binding to the 3' UTR causing either inhibition of translation of the mRA or degradation of that molecule, depending on the extent of complementary base pairing between the two molecules.
  101. short interfering RNA's (siRNAs)
    short double stranded RNAs that function in gene silencing by RNA interference RNAi
  102. degradation control
    the rate of RNA breakdown is regulated
  103. transmission genetics
    concerned primarily with genetic processes tht occur within individuals and how genes are passed from one individual to another. THE UNIT OF STUDY IS THE INDIVIDUAL
  104. molecular genetics
    interest is largely in the molecular nature of heredity.
  105. population genetics
    applies to the principles of transmission genetics to large groups of individuals, focusing on the transmission processes at one or a few genetic loci
  106. quantitative genetics
    considers the transmission of traits simultaneously determined by many genes
  107. hardy-weinberg law
    set of equations that describes the influence of random mating on the allele and genotypic frequencies of an infinitely large population
  108. genotype frequencies
    percentage of individuals within a population that have a particular genotype. the sum of the genotype frequencies at a given locus is 1.
  109. allele frequencies
    can be calculated in two equivalent ways from the observed number of different genotypes at a particular locus or from the genotype frequencies
  110. genetic drift
    if a population is limited in size, chance deviations from expected ratios can result in changes in allele frequency
  111. random mating
    mating between genotypes occurring in proportion to the frequencies of the genotypes in the population
  112. proportion of polymorphic loci
    calculated by dividing the number of polymorphic loci by the total number of loci examined
  113. heterozygosity
    the average proportion of heterozygous individuals in a population for many loci
  114. observed heterozygosity
    the number of individuals in the population that are heterozygous at that locus
  115. expected heterozygosity
    the number of heterozygotes expected if the population is in hardy-weinberg equilibrium
  116. restriction fragment length polymorphisms
    different patterns on the gel when the DNA from two individuals is mixed with the restriction enzyme and the resulting fragments are separated on a gel
  117. short tandem repeats (microsatellites)
    2-6 base pairs of DNA sequences tandemly repeated a few times up to about 100 times.
  118. forward mutations
    the mutation of A to a
  119. reverse mutation
    a to A
  120. effective population size
    the equivalent number of adults contributing gametes to the next generation
  121. founder effect
    another way in which genetic drift arises. it occurs when a population is initially established by a small number of breeding individuals
  122. bottleneck effect
    form of genetic drift that occurs when a population is drastically reduced in size.
  123. pleiotropic effects
    single genes that have effects on different aspects of the life cycle that effect fitness
  124. heterosis (overdominance/heterozygote superiority)
    the simplest type of balancing selection. a form of natural selection that works to maintain genetic polymorphisms in a population
  125. positive assortative mating
    non random mating that occurs when individuals with similar phenotypes mate preferentially
  126. negative assortative mating
    occurs when phenotypically dissimilar individuals mate more often than do randomly chosen individuals
  127. inbreeding
    involves preferential mating between relatives
  128. gametic disequilibrium
    when deviations from hybridization, genetic drift, and migration cause alleles at two loci appear to segregate together
  129. linkage disequilibrium
    deviations from the expectations of independent assortment and Hardy-Weinberg equilibrium caused either by physical linkage or population demography
  130. population viability analysis
    techniques designed to estimate how large a population must be to keep from going extinct for a particular period of time with a degree of certainty.
  131. postzygotic isolation
    may inclue hybrid sterility, hybrid inviability, or hybrid breakdown
  132. prezygotic isolation
    may keep the species apart in many diferent ways
  133. temporal isolation
    by changing the mating season or the activity periods such that they no longer overlap, the opportunity for mating is removed.
  134. ecological isolation
    if the ecological niche of the two species is distinct, such that, for example, the two species dietary preferences keep them geographically isolated, even on a small spatial scale, again the opportunity for mating is removed.
  135. behavioral incompatibility
    if the two species recognize and avoid each other as mates, there is no opportunity for mating
  136. mechanical isolation
    the two species may not be able to discriminate one from another, but if their genitalia do not fit together, zygotes cannot be formed.
  137. gametic isolation
    even if they mate and gametes come in contact with one another, there still remains a highly complex process of gametic fusion that can fail.
  138. multifactorial traits
    traits that are influenced by both environment and genotype
  139. polygene (multiple gene hypothesis for quantitative inheritance)
    an explanation that quantitative traits are controlled by many genes.
  140. contributing alleles
  141. noncontributing alleles
    non functional
  142. polygenes
    allele pairs at a number of loci that have a small effect on the overall phenotype
  143. frequency distribution
    a summary of a group in terms of the proportion of individuals that fall within a certain phenotypic range.
  144. correlation coefficient
    a statistic that measures the strength of the association between two variables in the same experimental unit, which in genetics is usually an individual.
  145. covariance
    a measure of how much variation is shared by an individual for both traits.
  146. phenotypic variance
    a measure of all variability for a trait
  147. genetic variance
    the genetic contribution to the phenotypic variation
  148. environmental variance
    includes any nongenetic source of variation
  149. heritability
    the proportion of a populations phenotypic variation that is attributable to genetic factors
  150. quantitative trait loci
    the individual loci that contribute to a quantitative trait
  151. Regina George is a
    Scum sucking road whore
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